Method and apparatus for the recording and reproducing of data on a storage medium

ABSTRACT

A recording medium has a user recordable area in which two types of information may be recorded, such as audio data and user data, and a control area having a first area for management information regarding the first type of information and a second area for management information regarding the second type of information. A reproducing apparatus uses the first management information to reproduce the first type of information and to avoid reproducing the second type of information as the first type of information, and uses the second management information to reproduce the second type of information and to avoid reproducing the first type of information as the second type of information. A recording apparatus generates the first management information when the first type of information is recorded and generates the second management information when the second type of information is recorded.

This application is a division of application Ser. No. 08/196,469, filedFeb. 15, 1994, pending.

BACKGROUND OF THE INVENTION

The present invention relates to a recording medium, a recordingapparatus and a reproducing apparatus therefor. The recording medium isfor recording multiple types of data, such as audio data and user data,and has separate management information for each of the data typesrecorded thereon.

A magneto-optical (MO) recording medium, specifically, a disc, arecording apparatus and a reproducing apparatus therefor have recentlybecome available to consumers for reproduction and recording of audioinformation, such as audio programs.

This MO disc includes a user recordable area in which audio files can berecorded by the consumer and a management information area forcontaining data about each of the audio files, such as its contents andstarting and ending positions. For content identification, it issufficient to distinguish the audio files merely by numbers.

The management information in this MO disc can accommodate a relativelysmall number of audio files, for example, up to 255 audio files. This isappropriate since it is unlikely that a larger number of small audiofiles, corresponding to, for example, very short programs, will berecorded.

It is desirable that the MO disc be able to record and reproduceadditional, non-audio data, referred to herein as user data, forexample, character and graphic information, which is not in the formatdefined for audio data.

For user data, management information is needed in addition to thatheretofore used for identifying each data file and its position withinthe recordable area. For example, a more extensive file namingcapability, and attribute information including data describing the userdata to an external device are desirable. It is also desirable that themanagement information structure for user data be able to accommodate alarge number of small user data files.

Since the nature of the management information suitable for audio datais different than the nature of the management information suitable foruser data, the type of management information defined for the presentlyavailable MO disc makes it practically impossible for this MO disc to beused more generally to record and reproduce non-audio data.

In conventional disc media used for recording and/or reproducing userdata, such as floppy discs, a data management structure has been adoptedin which directory information for data files is spread across the disc.Specifically, a root directory is at a predetermined location. The rootdirectory can include pointers to user data files and tosub-directories, also referred to as child directories. The childdirectories are recorded in the user recordable area of the disc,interspersed among the user data files. The child directories caninclude pointers to user data files and to their own sub-directories,which are grandchild directories relative to the root directory. Thegrandchild directories can include pointers to user data files and totheir own sub-directories, which are great-grandchild directoriesrelative to the root directory.

To access a file in a grandchild directory, the reproducing apparatusmust first access the root directory, then the child directory, then thegrandchild directory, and then the file itself within the grandchilddirectory. Since the child and grandchild directories may be recorded atvarying locations on the disc, multiple disc read operations are oftenrequired to access the appropriate directory, which results in anoticeable delay to the user.

OBJECTS AND SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide a recordingmedium, a recording apparatus and a reproducing apparatus for use withthe recording medium which avoid the aforementioned disadvantages of theprior art.

It is another object of the present invention to provide a recordingmedium, recording apparatus and reproducing apparatus which expands aconventional MO disc audio recording and reproducing system so that theMO disc system can also be used to record and/or reproduce non-audiodata.

It is a further object of the present invention to expand theconventional MO disc audio recording and reproducing system so that itcan be used to record and/or reproduce audio and non-audio data usingthe same MO disc.

It is yet another object of the present invention to reduce access timefor directory information stored on the recording medium.

In accordance with an aspect of this invention, a recording medium hasrecorded thereon first management information for use with a first typeof information that may be recorded on the recording medium, and secondmanagement information for use with a second different type ofinformation that may be recorded on the recording medium, the first andsecond management information being recorded in respectively differentareas.

As another aspect of this invention, reproducing apparatus provides forreproducing the first and second management information from therecording medium, and the reproduced first management information isused to recover the first type of information and to prevent the secondtype of information from being erroneously interpreted as information ofthe first type. Similarly, the reproduced second management informationis used to recover the second type of information and to prevent thefirst type of information from being erroneously interpreted asinformation of the second type.

As a further aspect of this invention, recording apparatus is providedfor recording the first management information, the second managementinformation and the first and second types of information in first,second and third areas, respectively, on the recording medium, the firstmanagement information being generated only when the first type ofinformation is recorded and the second management information beinggenerated only when the second type of information is recorded.

The above, and other objects, features and advantages of the presentinvention will be apparent from the following detailed description ofthe preferred embodiments of the present invention when read inconjunction with the accompanying drawings in which corresponding partsare identified by the same reference numeral.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exterior view of a recording medium and a recording and/orreproducing apparatus according to the present invention;

FIG. 2 is a block diagram of the recording and/or reproducing apparatusof FIG. 1;

FIGS. 3, 4 and 5 are diagrams showing the usage of the recording mediumaccording to the present invention;

FIG. 6 is a diagram showing the P-TOC provided on the recording mediumaccording to the present invention;

FIG. 7 is a diagram showing the U-TOC provided on the recording mediumaccording to the present invention;

FIG. 8 is a diagram used for explaining a link structure of U-TOCinformation;

FIG. 9 is a diagram used for explaining data U-TOC information;

FIGS. 10, 11 and 12 are diagrams of the CAT0, CAT1 and CAT2 sectors,respectively, of the data U-TOC information;

FIG. 13 is a diagram used for explaining a unit of CAT information;

FIG. 14 is a diagram used for explaining a portion of the unit of CATinformation of FIG. 13;

FIG. 15 shows a directory sector of the data U-TOC information;

FIG. 16 shows an example of a directory hierarchical structure which maybe represented in the data U-TOC information;

FIGS. 17 and 18 are diagrams showing heading sectors for character anddot data, respectively, represented in the data U-TOC information;

FIGS. 19-22 are diagrams showing the structure of data sectors on therecording medium according to the present invention; and

FIG. 23 is a flow chart of operation of the recording/reproducingapparatus according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In accordance with the present invention, a recording medium hasrecorded thereon separate management information for the various typesof information expected to be recorded by a user, such as audio data andnon-audio data, the non-audio data being referred to herein as userdata, for example, character and graphic information. The recordingmedium may be an MO disc, and thus the utility of the already availableMO disc is increased.

By providing separate management information for the various types ofinformation that may be recorded by a user, so-called backwardcompatibility of the MO disc is achieved with existing apparatussuitable for recording and reproducing only audio information. That is,a recording medium according to the present invention may be used withapparatus expecting a recording medium in the already availableaudio-only format.

The management information for audio data considers an area used forrecording user data to be an unrecordable and unreproducible area.Similarly, the management information for user data considers an areaused for recording audio data to be an unrecordable and unreproduciblearea. Thus, errors in reproduction and erasing due to confusion betweentypes of information are prevented.

The portion of the recordable area which is used for user data isdefined within the management information for audio data. This ensuresthat the user data area is transparent to an audio reproducingapparatus, that is, the audio reproducing apparatus ignores the portionof the recordable area containing the user data even if the audioapparatus is able to detect and operate with only management informationfor audio data and not with management information for user data. Whenaudio data is recorded, only the management information for audio dataneeds to be updated, that is, the management information for user dataneed not be updated. Consequently, a recording apparatus for audio onlycan be used without any modification or retrofitting whatsoever with adisc according to the present invention. When an audio file is recorded,the management information for audio data can be quickly updated, sincechanges need not be made to the management information for user data.

When a user data file which exceeds the capacity of the area allocatedfor user data is to be recorded, the user data area can be extended byappropriately adjusting the boundaries of the user data area definedwithin the management data for audio data. When the user data file isrecorded, the management information for user data is suitably updated.

All of the directory information for the user data files is recorded inthe management area for user data files. Since all generations, i.e.,parent, child and so on, of directory information for a user data fileare usually read during the same disc access, directory access time isreduced relative to conventional directory arrangements.

The management information for user data includes reference informationfor each user data file, such as a text excerpt for a document file oran image portion or icon for a graphics file. The reference informationmakes it easier for a user to retrieve a file. Since the referenceinformation is part of the management information which is generallylocated in one place on the disc, the reference information isimmediately available, that is, there is no time penalty resulting fromstill another disc access. Keyword searches, for example, may be quicklyperformed on the reference information, even though performing a similarkeyword search on the user data files would require an unacceptably longtime.

FIG. 1 generally shows an external view of a recording medium 1 and arecording and/or reproducing apparatus 10 according to the presentinvention.

The recording medium 1 is a MO disc adapted to be stored in a cartridgeK having a shutter S which is operative to slide to expose a recordingface of the MO disc.

The disc 1 described herein is a MO disc which permits recording ofaudio and non-audio data and also has an area in which certainmanagement information is optically (read only) pre-recorded. Thepresent invention also contemplates use of an optical, or pre-mastered,disc on which user reproducible information is permanently recorded. Thepresent invention further contemplates use of a hybrid type of dischaving a read only area containing optically pre-recorded audio and/ornon-audio data, and also having a MO area in which the user may recordaudio and/or non-audio data.

The recording/reproducing apparatus 10 has a disc inserting section 11which functions to allow insertion of the cartridge K. The apparatus 10has an internal mechanism, not shown for ease of illustration, which isadapted to slide open the shutter S when the cartridge K is inserted inthe disc inserting section 11.

The apparatus 10 has a key input section 12 adapted to be operated by auser. The key input section 12 may include cursor movement keys, anenter key, data input keys or the like.

The apparatus 10 also has a display section 13 which functions todisplay information including menu information for retrieving data andthe retrieved data.

In one embodiment, the apparatus 10 includes an image scanner section 14which is adapted to detect image information on a sheet of paper and toconvert the image information into graphic data, also referred to as dotdata. The apparatus 10 is operative to record image data inputtedthrough the image scanner 14 on the MO disc 1.

Preferably, the apparatus 10 further includes an input/output connectorsection 15 which functions to transmit and/or receive data to/from otherdata processing machines, such as computers and word processors, througha communication cable C.

The apparatus 10 may further include a terminal 16 for inputting and/oroutputting audio signals from/to other audio apparatus through an audiocable 17.

FIG. 2 shows a functional block diagram of the recording and/orreproducing apparatus 10 having the MO disc 1 loaded therein.

A spindle motor 22 functions to rotate and drive the disc 1 loadedthereon. An optical head 23 is operative to irradiate laser light to thedisc 1 during recording and reproduction operations.

During recording, the laser head 23 outputs high level laser light toheat a given spot on the magnetic layer of the recording tracks to atemperature above the Curie temperature, which effectively dissipatesthe magnetization of the given spot. The disc continues rotation, andonce away from the laser beam, the spot begins to cool. A magnetic head26, disposed on the other side of the disc 1 from the laser 23, isadapted to then apply a magnetic field to the spot to orient it toeither north or south polarity, corresponding to the "1" or "0" to berecorded thereon.

During reproduction, the head 23 outputs relatively low level polarizedlaser light, which is reflected by the disc and processed to form areproduced signal.

As discussed in detail below, the disc 1 actually has two areas, apre-mastered playback-only area in which information is recorded as pitsin tracks, and a user recordable and reproducible MO area in whichinformation is recorded as magnetized regions in tracks. Duringmanufacturing of the disc, the MO area is provided with grooved tracks,referred to as pre-grooves, which are shifted slightly, or wobbled, tocreate address information. These pre-grooves enable tracking andspindle servo control during recording and reproducing. When trackingproperly, the laser beam spot is centered on the grooved portion of atrack.

In the pre-mastered area of the disc, light reflected directly back tothe laser indicates the absence of a pit, while in the presence of apit, the light is diffracted and a lower level is reflected back to thelaser. While scanning the pre-mastered regions of the disc 1, the head23 senses changes of reflected light level caused by the existence ofpits.

In the MO area of the disc, upon striking a specific portion of thedisc, the polarized light from the laser will be reflected back alongone of two opposing directions, with the polarization plane rotatingslightly in a forward or reverse direction in accordance with thedirection of the magnetic signal, in a phenomenon known as the Kerreffect. The reproduced information can be distinguished by sensing whichpolarization direction predominates in the reflected light.

To receive the reflected light, an optical system comprising adeflecting beam splitter, an objective lens 23a and the like and adetector for detecting reflected light are mounted on the optical head23. The objective lens 23a is held by a bi-axial mechanism 24 in amanner capable of altering its orientation in the disc radial directionand in the direction approaching to or separated from the disc. Further,the whole optical head 23 is adapted to be able to move in the discradial direction by a suitable drive assembly such as thread mechanism25.

An RF amplifier 27 is adapted to receive a reproduced signal from theoptical head 23, to process the supplied information and to extract areproduced RF signal, tracking error signal, focus error signal,pre-groove information, address information, sub-code information, focusmonitor signal and the like. The amplifier 27 functions to supply thethus extracted reproduced RF signal to a decoder section 28, and tosupply the pre-groove information to an address decoder 40, which isoperative to obtain absolute position information and to supply theabsolute position information to the decoder 28. The decoder 28 isoperative to supply the absolute position information and the addressinformation (the latter having been recorded as data) to the systemcontroller 21.

The amplifier 27 functions to supply the tracking error signal and focuserror signal to a servo circuit 29; and to supply the focus monitorsignal to system controller 21. The controller 21 may be a microcomputerand is adapted to supply a track jump command, seek command, rotationalvelocity sensing information or the like to the servo circuit 29.

The servo circuit 29 is operative to produce various servo drive signalsbased on the supplied tracking error signal and focus error signal andthe information from the system controller 21, to control the bi-axialmechanism 24 and thread mechanism 25 for focussing and tracking, and tocontrol the spindle motor 22 in a constant angular velocity (CAV) orconstant linear velocity (CLV) operation.

The decoder 28 is also operative to decode the reproduced RF signal,which may represent user data or audio information, usingeight-to-fourteen modulation (EFM) decoding, cross interleaveReed-Solomon code (CIRC) decoding (used in the pre-mastered area of thedisc), advanced CIRC (ACIRC) decoding (used in the MO area of the disc)and the like, and to supply a decoded reproduced signal to the systemcontroller 21.

In a complementary manner, during a recording operation, information issupplied from the system controller 21 to an encoder 30, which isoperative to encode the information using ACIRC encoding, EFM modulationand the like and to supply the encoded signal to a magnetic head drivingcircuit 31 which applies the encoded signal to the magnetic head 26.During recording, the system controller 21 is operative to supply acontrol signal to the optical head 23 that causes the head 23 to outputrecording level laser light.

During playback, the reproduced signal is supplied from the controller21 to a conversion memory 32 which functions to convert code data tofont data and to process the font data so it can be displayed ascharacter data or the like. A buffer RAM 33 functions to store displaydata to be displayed on the display section 13.

A display controller 35 is adapted to control displaying of data fromthe system controller 21 and buffer 33, such as a retrieval menu anddata read from the disc 1, on the display section 13.

The image scanner 14 supplies scanned data to the RAM 33 which functionsas a temporary memory for temporarily holding the scanned or dot datafrom the image scanner 14.

A communication circuit 34 transmits/receives data to/from an externaldevice through the connector section 15. The RAM 33 also stores datatransmitted to or received from the connector section 15.

In addition, the RAM stores audio data and/or user data read from thedisc 1.

Audio information is reproduced in a similar manner as user datainformation. However, compressed audio signals are read from the disc inintervals at a rate of 1.41 Mbit/sec because the data pickup rate isabove five times faster than is required for playback. An advantage ofinterval playback is that even if the signal flow is interrupted due toshocks or movement, an audio signal is output to the user based on theinformation already stored in the RAM 33 thereby hiding the interruptionin signal flow from the user. When normal playback is resumed, thecontents of the buffer 33 are replenished. More specifically, the RAM 33is adapted to supply data to a sound compression decoder section 38 at arate of 0.3 Mbit/sec, that is, about 1/5 of the reproducing rate of 1.4Mbit/sec. The decoder 38 is adapted to decompress audio data which wascompressed by a sound compression encoder (for example compressionencoder 37 may be used to record audio information on disc 1), and tosupply the decompressed audio to a D/A converter 39 that functions tosupply analog audio signals, such as left channel L and right channel Raudio signals, to terminals 16b.

Audio signals to be recorded are received at terminals 16a from theaudio cable 17 or from a microphone, not shown, and applied to an A/Dconverter 36 that functions to convert the left and right channel analogaudio signals into quantized 16 bit digital data having a samplingfrequency of 44.1 Kbit and to supply the digital audio data to anencoder 37. The encoder 37 is adapted to compress the audio data using acompression system designed specifically for audio. The compressionsystem utilizes the fact that the sensitivity of the human ear dependson frequency, and also utilizes the masking effect, that is, the factthat a soft sound can be rendered inaudible by a louder sound. Theregions of the audio signal to which the human ear is most sensitive aremost accurately recorded, while the other regions are less accuratelyrecorded. Since the least accurate recording is in the portion of thesignal to which the ear is least sensitive, inaccuracies are unlikely tobe noticed. The compression encoder 37 supplies the compressed audiodata to the RAM 33. The system controller 21 reads the compressed audiodata from the RAM 33, and supplies it to the encoder 30 at predeterminedtimes. The encoder 30 encodes the audio data using CIRC or ACIRCencoding, EFM modulation and the like and supplies the encoded audiodata to the magnetic head driving circuit 31, which causes the magnetichead 26 to apply a north or south magnetic field to the disc 1 while thesystem controller 21 supplies control signals to the optical head 23 sothe head 23 outputs recording level laser light.

FIG. 3 shows an overview of the areas of the disc 1.

The leftmost column of FIG. 3 shows two physical regions, a pre-masteredregion in which data is recorded as pits, and a user recordable regionin which data is recorded magneto-optically in pre-grooves, that is,wobbled tracks formed during manufacturing of the disc. The outermostportion of the user recordable area is a lead-out area in which data isnot recorded.

The next-to-leftmost column of FIG. 3 shows the logical structure, ormemory map, of information recorded on the disc.

The minimum unit for a recording or reproducing operation carried out ona recording track of the disc 1 is defined to be a cluster. Each clusteris defined as including 36 sectors. The first four sectors in a clustergenerally contain sub-data and linking information while the remainingthirty-two sectors generally contain main data, that is, managementinformation or information for playback by the user, such as audio dataor non-audio data. The nature of the main data depends on where on thedisc the cluster is located.

A pre-mastered table of contents (P-TOC) is recorded in the pre-masteredarea. The P-TOC has a length of at least one cluster and is recordedthree times so that the disc is usable despite an unrecoverable error inone of the P-TOCs. The information in the P-TOC specifies areas such asa recordable user area on the disc and provides management informationfor read only areas on the disc, not shown in FIG. 3, such as programsrecorded on a pre-mastered or hybrid disc.

At the start of the user recordable area, there is a control areacontaining a first area containing rewritable signals representing firstmanagement information for signals representing a first type ofinformation recorded on the disc 1, namely, audio data, such as audioprograms. The first management information is a table of contents foruser audio data (A-UTOC). The A-UTOC occupies at least one cluster andincludes a series of pointers to other portions of the A-UTOC which arethemselves pointers to unused areas on the disc and areas in which audiodata are recorded.

The control area also contains a second area containing rewritablesignals representing second management information for signalsrepresenting a second type of information recorded on the disc 1,namely, non-audio data, such as character or graphic image (dot) data.The second management information is a table of contents for usernon-audio data (D-UTOC). The D-UTOC occupies at least one cluster.Following the sectors of the D-UTOC containing sub-data information, thefirst three main information sectors of the D-UTOC are clusterallocation tables (CATs) which indicate the status and linkage of eachcluster in the user recordable area, the next (fourth) main informationsector of the D-UTOC is a root directory, and each of the remaining 28main information sectors of the D-UTOC is either a child directorysector, a heading sector for character data files or a heading sectorfor dot data files. The child directories may be of any generationrelative to the root directory, that is, child, grandchild,great-grandchild and so on.

Each of the A-UTOC and the D-UTOC is recorded in triplicate to provideerror protection.

The P-TOC contains a pointer to the position of the first managementarea, located at address UST_(A). The position of the second managementarea is the address UST_(A) plus a predetermined offset which isdiscussed further below.

Following the control area is a recordable area in which the user audioand/or non-audio data is recorded.

Three audio files are shown as M₁, M₂ and M₃. The A-UTOC containsmanagement information for these audio files. Although not shown, thesectors containing audio data are further divided. A set of two sectorsis divided into 11 regions, each called a sound group.

An area for recording user data files is shown as D₁. Managementinformation in the A-UTOC defines the boundaries of the area D₁ whilethe D-UTOC contains management information for the user data files inthe area D₁. Each cluster in the user data contains, as explained above,32 sectors in which user data may be recorded and, as explained below,each of these sectors has an area of 2048 bytes available for recordinguser data. Thus, each cluster can have up to 2048×32=65,536 bytes ofuser data recorded therein, which is 64 Kbytes (1 Kbyte=1024 bytes) orabout 65,000 bytes.

The P-TOC contains a pointer to the start of the recordable areaRST_(A), shown as address 0032h in this example, where "h" indicateshexadecimal notation.

When data is to be read to or reproduced from the disc 1, the apparatus10 reads the P-TOC to obtain the pointer to the start of the A-UTOC. Theapparatus 10 reads the A-UTOC into its buffer memory 33, determines theposition of the D-UTOC and reads the D-UTOC into its memory 33. If nodata U-TOC exists, the disc is determined to be a virgin disc on whichno data is recorded and the data U-TOC is initialized.

Audio data can be recorded with reference only to the A-UTOC, exceptthat the P-TOC is referenced to obtain the start of the user recordablearea RST_(A). Audio data is reproduced with reference to the P-TOC, forpre-mastered audio information, and with reference to the A-UTOC, foraudio information recorded by the user.

User data can be recorded and reproduced with reference only to theD-UTOC, as long as the capacity of the area D₁ is sufficient.

If additional user data capacity is needed on the disc, the A-UTOC mustfirst be adjusted to define additional space for user data, such as byenlarging the area D₁ or by defining a new user data area D₂. Managingthe user data area in this manner prevents an attempt to reproduce theuser data as audio data.

When a change is made to the A-UTOC or the D-UTOC in the RAM 33 such asrecording or erasing data, the controller 21 rewrites the respectivemanagement information on the disc 1, in triplicate, to reflect thechange.

Even if the disc 1 is used only for recording non-audio data, the audioU-TOC is needed to distinguish the management areas for audio andnon-audio data. Furthermore, the start address of the audioU-TOC,defined in the P-TOC, is needed to determine the start address ofthe data U-TOC.

FIG. 4 shows the physical layout of the disc 1 in more detail.

The pre-mastered area wherein the P-TOC is recorded is located at theinnermost portion of the disc.

The grooved area is defined as having cluster addresses from "0000h" to"0BFFh". The clusters having addresses from "0000h" to the start of thelead out area RO_(A) form a recordable area wherein information isrecorded magnetically and reproduced optically.

In this recordable area, a recordable user area in which a user mayrecord data, including audio and non-audio data, is located at addressesfrom the recordable user area start address RST_(A) (for example,cluster address "0032h" to the lead out start address RO_(A).

At cluster addresses from "0000h" to RST_(A) ("0032h"), there is locateda control area for different types of management data in which theA-UTOC and D-UTOC may be recorded. In the control area, one powercalibration cluster located at address PC_(A) is provided as an area forcalibrating laser power.

When the A-UTOC is located towards the beginning of the control area,specifically, at or before cluster address "0020h", the D-UTOC islocated after the A-UTOC. Specifically, the start of the D-UTOC is acluster address offset for example by "10h" from the starting positionof A-UTOC which is indicated by the A-UTOC start address USTA in theP-TOC.

Alternatively, when the A-UTOC is located towards the end of the controlarea, specifically, after cluster address "0020h", the start of theD-UTOC may be a cluster address offset from the starting position of theA-UTOC for example by "-10h".

FIG. 5 is a diagram showing management of the recording medium by theA-UTOC and D-UTOC. The leftmost column generally shows how therecordable area is perceived by the data U-TOC. The rightmost columngenerally shows how the recordable area is perceived by the audio U-TOC.For convenience, the P-TOC is shown in the rightmost column.

The audio U-TOC manages the audio data in the recordable user area fromthe recordable user area start address RST_(A) to the lead out startaddress RO_(A) and manages the boundaries of the non-audio data areatherein. FIG. 5 shows three audio files M1, M2, M3 recorded on thedisc 1. The A-UTOC contains three parts describing the start addresses,end addresses and modes of the respective audio files. A mode bit, bitd4 discussed further below, is set to a value indicating that each ofthe files M1, M2, M3 is audio data.

The A-UTOC contains a fourth part indicating the start and end addressesDST_(A), DE_(A), respectively, of the non-audio data area D₁. A mode bitin the fourth part is set to a value indicating that the area D₁ isnon-audio data. Otherwise, the non-audio data area is treated by theA-UTOC essentially as a special type of audio file.

The A-UTOC also contains parts indicating that regions NA1, NA2 are freeareas, that is, empty areas available for recording data. The areas NA1,NA2 could in fact contain data from a file which had been erased, thatis, erasing a file generally corresponds to indicating that its clustersare available for use and not necessarily to erasing the user data fileitself. The areas NA1, NA2 are linked together in a list of free areasmaintained in the audio U-TOC.

The data U-TOC manages non-audio data files in the non-audio data areadefined in the audio U-TOC. FIG. 5 shows four data files DF1-DF4recorded on the disc 1. The remainder of the data area D₁ is seen to bean empty area EA which can be used for recording additional non-audiodata.

Directories in the data U-TOC manage file names, extensions, updatedates, addresses and linking information for the user data files. Aswill be explained, data for one data file may be recorded innon-contiguous tracks on the recordable area. The cluster allocationtable (CAT) in the D-UTOC indicates the status of each cluster in therecordable area of the disc 1. The CAT identifies the empty area EAusing a predefined value for each cluster of the empty area, such as"Fh". When a data file is erased, the CAT reflects the erasure bychanging the values for the clusters in the erased data file to thepredefined value ("Fh").

The data U-TOC considers the regions WA1 and WA2 in the control area asstoring the audio management information A-UTOC and the non-audiomanagement information D-UTOC. The CAT reflects the status of theregions WA1 and WA2.

The data U-TOC considers regions PRW1-PRW4 in the recordable area asregions in which reading and writing are prohibited. The CAT indicatesthat recording and reproduction is prohibited in the clusters of theregions PRW1-PRW4. The regions PRW1, PRW2 correspond to unused portionsof the control area. The region PRW3 corresponds to an unused portion ofthe control area and to the area in which audio files M1, M2, M3 arerecorded. Thus, the D-UTOC prevents the audio files from being accessedand reproduced erroneously as user data and prevents the audio filesfrom being destroyed due to erroneous writing of a user data file overthe audio files. The region PRW4 corresponds to the lead out area.

The CAT of the data U-TOC indicates that recording is inhibited(prohibited) in the clusters of the areas NA1, NA2.

FIG. 6 is a diagram showing one sector of the P-TOC provided on the disc1.

A sector of the P-TOC comprises, for example, a region of 588 rows (row0 to row 587), each four bytes wide. The start of the P-TOC is a headercontaining synchronous patterns having bytes that contain all zero bitsor all "1" bits, followed by three address bytes for cluster and sectoraddresses.

Following the header, there is an identification area containing anASCII code, such as "MINI".

Following the ASCII identification code, there are recorded a disc type,recording level, the number of the first recorded track (First TNO), thenumber of last recorded track (Last TNO), the lead out start addressRO_(A), the laser power calibration CAL area start address PC_(A), thestart address of the audio U-TOC UST_(A) and the start address of theuser recordable area RST_(A).

Next is recorded a table containing pointers P-TNO 1 through P-TNO 255which each correspond to one of up to 255 audio pieces which can bepre-mastered on the disc. These pointers point to management informationwithin the P-TOC.

When the disc is used for recording data only or when no pre-masteredaudio area exists on the disc, each byte of the pointers P-TNO 1 throughP-TNO 255 is set to "00h".

Following the region of 255 audio pointers, there is a management tablesection having 255 parts, numbered from (01h) to (FFh). Each part can bepointed to by one of the pointers P-TNO 1 through P-TNO 255.Specifically, a pointer P-TNO contains data having the value of the partnumber plus an offset corresponding to where the parts table ispositioned relative to the start of the sector. Each part contains astart address and an end address for an audio segment such as a program,where "segment" is used to mean contiguous tracks in which the data forthe audio file are continuously recorded. Each part also contains onebyte (eight bits d1-d8) of mode information (track mode) for thesegment. The bits of the mode information byte are used as follows:

    ______________________________________                                        Mode bit   Meaning                                                            ______________________________________                                        d1         whether the segment is recordable or non-                                     recordable                                                         d2         whether the segment is copyright protected                         d3         whether the segment is an original or a copied                                record on and after the second generation                          d4         whether the segment is audio or non-audio data                     d5, d6     whether the segment is normal audio                                d7         whether the segment is monaural or stereo                                     audio data                                                         d8         respective modes of emphasis processing of                                    data in the segment                                                ______________________________________                                    

It will be appreciated that mode bits d1 and d4 can be used to define aregion of the disc as non-recordable and non-reproducible, from theperspective of the P-TOC.

FIG. 7 is a diagram showing one sector of the audio U-TOC provided onthe disc 1.

The A-UTOC contains management information for audio files recorded bythe user and for areas in which audio information may be recorded by theuser.

A sector of the A-UTOC comprises, for example, a region of 588 rows,each four bytes wide. At the start of the A-UTOC is a header containingsynchronous patterns having bytes that contain all zero bits or all "1"bits, followed by three address bytes for cluster and sector addresses.

Following the header are recorded data such as a maker code, model code,number of first program (First TNO), number of last program (Last TNO),states of used sectors, disc serial number and disc ID.

Next is recorded a table containing a pointer to a list of defectiveareas P-DFA on the disc 1, a pointer to a list of unused parts P-EMPTYin the control table of the A-UTOC, a pointer to a list of free areasP-FRA, that is, unused tracks or segments, on the recordable portion ofthe disc 1 in which a user may record data, and pointers P-TNO 1 throughP-TNO 255 which each correspond to a respective audio piece recorded onthe MO portion of the disc by the user. These pointers point tomanagement information within the A-UTOC.

Following the pointers region, there is a management table sectionhaving 255 parts, numbered from (01h) to (FFh). Each part can be pointedto by one of the pointers P-DFA, P-EMPTY, P-FRA, and P-TNO 1 throughP-TNO 255. Each part contains a start address and an end address for anaudio segment such as a program, where "segment" is used to meancontiguous tracks in which the data for the audio file are recorded.Each part also contains mode information (track mode) for the segment,as described above with regard to the P-TOC.

In the case of A-UTOC sector 0, because a segment managed by a part ofthe parts table may be linked to another segment, each part can alsocontain link information indicating another part in the parts table inwhich a start address and end address of the segment to be linked arerecorded. The value of the link information is the physical location inthe A-UTOC of the linked part. Thus, recordable areas may be efficientlyused by dividing audio files and recording the divided portions in aplurality of segments that are physically discontinuous without suchdivision being noticeable to the user. This is particularly appropriatewhen the available recordable space on the disc is fragmented, whichcommonly occurs after a series of recording and erasing operations. Forexample, audio information comprising three linked segments has threecorresponding parts identifying the linked segments.

As another example, if P-DFA="(03h)" (actually, the value is theposition in the sector of the part 03h), the first entry in the list ofdefective parts is in part (03h), and the next entry is obtained withreference to the link information in the part (03h). If the linkinformation="(00h)", then this part is understood to be the last part ofthe list of defective areas on the MO disc.

Incidentally, since pre-mastered audio information is normally recordedcontinuously, that is, without division into physically discontinuousportions, the link information in the P-TOC shown in FIG. 6 is normallyset to "(00h)".

As another example, in a MO disc having no audio data recorded thereonand no defects, the pointer to unused areas of the parts tablesP-EMPTY="(01h)". The parts in the parts table have the following values:

    ______________________________________                                               Part Link information                                                  ______________________________________                                               01h  02h                                                                      02h  03h                                                                      03h  04h                                                                      . . .                                                                         FDh  FEh                                                                      FEh  FFh                                                                      FFh  00h                                                               ______________________________________                                    

Thus, it is readily seen that all of the parts in the parts table of theA-UTOC are empty and available for use.

FIG. 8 shows an example of representation of a list of free areas, thatis, areas on the MO disc available for recording by the user, havingfive entries or parts.

The pointer to the list of free areas P-FRA="(03h)", meaning that thehead of the list is the part (03h).

The part (03h) shows a start address of S03 and an end address of E03for the first free area on the MO disc. S03 and E03 are understood toindicate a physically contiguous region of tracks in the user recordablearea of the MO disc. The link information of part (03h)="(18h)",indicating that there is another free area on the MO disc.

Similarly, the part (18h) indicates a second physically contiguous freearea on the MO disc located from address S18 to E18. The linkinformation of part (03h) indicates that part (1Fh) identifies the nextfree area on the MO disc, which in turn indicates that part (2Bh)identifies the next free area on the MO disc, which in turn indicatesthat part (E3h) identifies the next free area on the MO disc. Since thelink information of part (E3h)="(00h)", the part (E3h) is seen to be thelast free area on the MO disc.

One of ordinary skill in the art will readily appreciate that audioinformation recorded on the MO disc may be identified in the same manneras described for the free areas on the disc. For example, a second audiofile recorded by the user on the MO disc is identified by the pointerP-TN02. The contents of P-TN02 indicate which part of the parts tablecontains position information for the first region of this second audiofile. The remaining regions of the second audio file can be indicated bya linked list of parts in the parts table, in the manner described abovefor the list of free areas. Since the sequence of segments in which datacomprising the second audio file are specified in this manner, theoptical head 23 and magnetic head 26 can be controlled to access andreproduce continuous audio information from discrete, physicallydiscontinuous segments thus efficiently utilizing the recording capacityof the MO disc.

It is an important feature of the present invention that the A-UTOC canmanage or allocate areas on the MO disc for user data recording usingthe above-described structure of linked lists of parts.

For example, when four programs are recorded and a certain area isdefined to be a general data area, each program is controlled bypointers P-TN01 through P-TN04 and the general data area is controlledby a pointer P-TN05 in the A-UTOC. The apparatus 10 uses the track modeinformation in the part indicated by the pointer P-TN05 to determinethat the region indicated by the addresses in this part contains usernon-audio data rather than audio data. Specifically, when bit d4 of themode information is set to, for example, "1", then the segment isdetermined to be non-audio data, also referred to as user data orgeneral data, while, when bit d4 is set to "0", the segment isdetermined to be audio data.

When non-audio data is recorded on the disc as read only pre-masteredpits, it is controlled in the same manner as the pre-mastered audiopieces in the P-TOC described above. Specifically, bit d4 of the modeinformation in the appropriate part of the parts table shown in FIG. 6is set to be "1" to distinguish the premastered non-audio data.

In the P-TOC and audio U-TOC, each address comprises 3 bytes (24 bits).The higher order 14 bits indicate a cluster address, the next 6 bitsindicate a sector address and the lower order 4 bits indicate a soundgroup address. These 4 bits are set to be "00h" or "1Ah".

Although there is no restriction that a start address controlled by theaudio U-TOC described above should be any particular sound groupaddress, in a case of audio data a convention is adopted in which astart address controlled by the audio U-TOC is set to address "00h" inthe sound group and an end address is set to address "1Ah" in the soundgroup in a case of general data area for recording non-audio data files.Thereby, audio data and non-audio data are prevented from existingtogether in a cluster.

FIG. 9 shows the data U-TOC cluster. Although the cluster contains 36sectors, the first four sectors used for sub-data are not shown, so thatFIG. 9 depicts only 32 sectors.

Each sector in a cluster used for recording management information foruser data, that is, the data U-TOC, or used for recording the user dataitself, includes a header comprising 16 bytes.

The first two bytes of the header contain a cluster address (Cluster H,Cluster L). The third byte of the header contains a sector address(Sector).

The fourth byte of the header contains CD-ROM specific mode information.

The fifth through eighth bytes of the header are address bytes (LogicalSector-0 to Logical Sector-3), for use by application programs.

The ninth byte of the header contains mode information (Mode) indicatingan error correction mode for the data recorded in the sector. Forexample, three types of error correction modes providing increasingamounts of error protection may be indicated as mode 0, mode 1 and mode2 in the Mode byte. Since the data area is the same for each of theerror correction modes, a recording/reproducing apparatus capable ofoperation only with the mode 0 format can operate with a sector in mode1 or 2 format, although without using the additional error protectioncapability available in mode 1 or 2. The error correction modes arediscussed further below.

The tenth byte of the header contains category information (Category)indicating an attribute of a data file, as discussed above.

When the category byte is "00h" it indicates that the sector isavailable for recording data.

For a sector in which user data is recorded, the category byte canindicate that binary, character or image data is recorded in the sector.It will be appreciated that binary data bytes are used by an applicationprogram.

For a sector in which management information for user data is recorded,i.e., one of the D-UTOC sectors, the category information indicateswhether CAT information, directory information or heading informationfor a user data file is recorded in the sector. During an erasingoperation, the controller 21 sets the category byte of a sector to"00h".

The eleventh byte of the header contains index information (Index)indicating a parameter of the data file. During an erasing operation,the controller 21 sets the index information of a sector to "00h".

The category byte values and following index byte values are defined asshown in the following table.

    ______________________________________                                                 Meaning of category byte                                             Category (what is recorded in                                                 byte     this sector)    Meaning of index byte                                ______________________________________                                        00h      this sector is unused.                                                                        --                                                   01h      binary data     size of the data area                                                         being used, in number                                                         ("00h" to "10h") of 128                                                       byte units                                           10h-1Fh  document data   size of the data area in                                                      number of 128 byte units                             20h-2Fh  one image (e.g., one                                                                          size of the data area in                                      scanned sheet) recorded                                                                       number of 128 byte units                                      as black and white dot                                                        data                                                                 30h-3Fh  multiple images (e.g., a                                                                      size of the data area in                                      plurality of scanned                                                                          number of 128 byte units                                      sheets) recorded as                                                           black and white dot data                                             E0h-E2h  allocation table (e.g.,                                                                       If sector is not used,                                        CAT)            the index byte is "00h".                                                      If sector is used, the                                                        index byte is nonzero.                               F0h-F1h  directory       the number (0 to 64) of                                                       directories recorded                                 FEh-FFh  heading         the number of heading                                                         parts recorded (0 to 32                                                       for document files, 0 to                                                      4 for dot image files)                               ______________________________________                                    

The twelfth byte of the header is reserved.

The last four bytes of the header contain identification information,usually four ASCII characters set to "MINX" by the controller 21 in thecase of non-audio or user data.

In the data U-TOC, the first three sectors (sector 00 to sector 02) areused for cluster allocation tables (CATs) CAT0 to CAT2. The fourthsector (sector 03) is used for a root directory. The remaining 28sectors (sectors 04 to 1Fh) are reserved for use as either childdirectories of the root directory or as heading sectors.

FIGS. 10, 11 and 12 are diagrams of the CAT0, CAT1 and CAT2 sectors,respectively. For each CAT, an ASCII identification code "MINX" isrecorded in the four ID bytes located at the end of the header toindicate that this sector is used for non-audio information. When thedata U-TOC is initialized or when it is rewritten, therecording/reproducing apparatus 10 records this "MINX" ID code in eachsector of the data U-TOC so that the D-UTOC can be distinguished fromthe P-TOC and the A-UTOC.

The tenth byte of the header of the CAT0 sector is set to "11100000"(E0h), the tenth byte of the header of the CAT1 sector is set to"11100001" (E1h), and the tenth byte of the header of the CAT2 sector isset to "11100010" (E2h), to identify the respective CAT sectors.

Each CAT has a data area comprising 2048 bytes. Each pair of bytes inthe CAT data area indicates the linkage status of a cluster in the userrecordable area, namely, the clusters "0000h" to "0BFFh" (3071) in FIG.4. The CAT0 contains information on clusters 0-1023, the CAT1 containsinformation on clusters 1024-2047 and the CAT2 contains information onclusters 2048-3071.

FIG. 13 shows one unit, that is, two bytes, referred to as a high byte Hand a low byte L, of information in the CAT data area. Each of theseunits corresponds to one cluster in the user recordable area. The twobyte unit is divided into words W0 to W3 each having four bits. The wordW0 indicates a category of the cluster and the words W1 to W3 are usedwhen the cluster is linked to another non-contiguous cluster, that is,when multiple clusters are used to represent a data file; when a lengthof consecutive empty clusters is indicated; or when coupling informationis indicated when the cluster is the head cluster of the data file.

FIG. 14 indicates the usage of the bits in the word W0 of each unit ofinformation in the CAT data area.

When the word W0="Fh", it indicates that the cluster is an empty clusteravailable for recording. The words W1 to W3 indicate a length ofconsecutive empty clusters following this cluster.

When the word W0="Eh", it indicates that the cluster is the end clusterof a data file.

When the word W0="Dh", it indicates that the cluster is followed byanother cluster representing the same data file.

When the word W0="Ch", it indicates that the cluster is a head clusterin a certain data file, and the words W1 to W3 indicate the nextcluster.

When the word W0="Bh", it indicates that a jump should be made from theinstant cluster to the cluster indicated by the words W1 to W3.

When the word W0="6h" to "1h", it indicates that the cluster is arecording inhibited cluster, more particularly:

"6h" indicates a cluster at the end portion of the data file,

"5h" indicates a cluster followed by a next contiguous cluster,

"4h" indicates a cluster at the head of the data file, and

"3h" indicates a cluster followed by a non-contiguous cluster at theaddress indicated by the words W1 to W3.

When the word W0="0h", it indicates that at least one of recording andreproduction is not permitted in the cluster. The word W0 correspondingto a cluster having audio information recorded therein is set to "0h".

The following table regarding head clusters will now be appreciated:

    ______________________________________                                        Value of  Value of each of                                                    word W0   words W1, W2, W3                                                                              Meaning                                             ______________________________________                                        Ch or 4h  000h            the data file continues                             indicating                in the next contiguous                              head cluster              cluster                                                       FFFh            the entirety of the data                                                      file is located in the                                                        instant (head) cluster                                        other           the data file continues                                                       in the non-contiguous                                                         cluster indicated by the                                                      words W1, W2, W3                                    ______________________________________                                    

For example, when one data file is recorded in four contiguous clusters,specifically, the zeroth to third clusters, this situation isrepresented in the CAT0 table as follows (* is an unspecified value):

    ______________________________________                                                   W0   W1         W2     W3                                          ______________________________________                                        CAT000 H, L  Ch     0          0    0                                         CAT001 H, L  Dh     *          *    *                                         CAT002 H, L  Dh     *          *    *                                         CAT003 H, L  Eh     *          *    *                                         ______________________________________                                    

Because recording tracks are formed spirally on the disc 1, data filesare frequently recorded on consecutive clusters. Accordingly, becausethe aforementioned CAT arrangement eliminates the need to consider thewords W1, W2 and W3 in many cases, it improves the efficiency of themanagement information for user data.

FIG. 15 shows the format of a directory sector of the data U-TOC. Theroot directory of the fourth sector (03h) and each of the childdirectories in the unspecified sectors (04h to 1Fh) have this format.

Sync information is located at the start of the sector.

Header information follows the sync information. The sector isidentified as a directory sector by its category information in thetenth byte of the header. When the tenth byte is "11110000" ("F0h"), thesector is the root directory. When the tenth byte is "11110001" ("F1h"),the sector is a child directory. The header information includes fourbytes of ASCII ID information set to "MINX" indicating that the sectoris used for non-audio data. The recording/reproducing apparatus 10refers to the ID information to determine the type of managementinformation stored in this sector.

A data area of 2048 bytes follows the header information. Each directoryentry in the data area occupies 32 bytes. Up to 64 directory entries canbe recorded in the data area of each directory sector. A directory entryprovides retrieval information for the data file to which itcorresponds.

The format of a directory entry is as follows.

Names of data files are recorded in the first eight bytes (Name 0 toName 7). The extension portion of file names are recorded in thefollowing three bytes (Suffix 0 to Suffix 2).

Category information is recorded in one byte of each directory entryfollowing the extension, and indicates an attribute of a data file towhich the directory entry corresponds. Category information is discussedfurther below.

Volume information is recorded in four bytes (Volume 1-0, Volume 1-1,Volume 2-0, Volume 2-1) of each directory entry following the categorybyte. The first two bytes of the volume information indicate the numberof clusters occupied by the data file to which the directory entrycorresponds, that is, how many clusters need to be accessed to reproducethe data file. The last two bytes of the volume information indicate thememory capacity needed by a host device to receive and use the data filecorresponding to this directory entry. The volume information is set to"00h" to indicate it is undefined.

Heading sector index information is recorded in two bytes (Index 0,Index 1) of each directory entry following the volume information. Whena heading sector for the data file corresponding to the directory entryis in the same cluster as the directory sector for this data file, thesector number of the heading sector is recorded as the first headingsector index byte (Index 0) and the heading part number (describedlater) within the sector of the heading sector is recorded as the secondheading sector index byte (Index 1). When the heading sector is in adifferent cluster than the directory sector, the first heading sectorindex byte is set to "00h".

Following the heading sector index information in each directory entry,there is a reserved byte.

Date information is recorded in five bytes (Year, Month, Day, Hour andMinutes) following the reserved byte in each directory entry, indicatingwhen the data file to which the directory entry corresponds was lastupdated.

Address information for the data file to which the directory entrycorresponds is recorded in three bytes (Cluster-H, Cluster-L and Sector)following the date information.

A directory can include directory entries only for child directories,that is, a directory is prohibited from indicating directories more thanone generation distant from itself.

When the data U-TOC is initialized, the root directory is created in thefourth sector (sector 03) of the data U-TOC. When a child directory iscreated, an entry therefor is provided in the root directory, indicatingthe address of the child directory. This process is repeated whenadditional directories are created in the child directory.

It is a feature of the present invention that all directory informationrequired to access a file can be retrieved using only one disc access,as long as all the directory units exist within one cluster. Multipleclusters are used for the data U-TOC only when the managementinformation for the user data exceeds the capacity of one cluster, thatis, there are very many short files recorded on the disc 1.

Up to 28 directory sectors can exist in a data U-TOC cluster. Eachsector can include 64 directories. Thus, 1792 directories can be definedwithin a data U-TOC cluster. If additional directories are needed, anadditional cluster for child directories can be provided at an arbitrarylocation in the recordable user area. This additional cluster isrecorded in triplicate in consecutive clusters.

FIG. 16 shows an example of a directory hierarchical structure which maybe represented in the data U-TOC management information.

Each block in FIG. 16 corresponds to a directory entry indicating adirectory (DIR) or a heading file (File). The lefthand column of FIG. 16indicates in which sector of the data U-TOC the directory entry isrecorded. The solid line arrows indicate a child directory, and in whichsector the child directory entry is recorded. The broken line arrowsindicate a data file and its corresponding cluster in the userrecordable area.

As an example, to retrieve the directory information for a data file"FileE", the root directory (DIR0) is accessed, then its child directory(DIR1), then its grandchild (DIR3), then its great-grandchild (DIR4),which contains the directory entry for "FileE". This directory entryindicates that the address of "FileE" is cluster 500. Since alldirectory entries are located within the same cluster, only one discaccess is required to obtain the directory information for this file. Ifthis cluster has previously been read into the RAM 33, then no discaccesses are required.

FIGS. 17 and 18 are diagrams showing heading sectors for character anddot data, respectively, represented in the data U-TOC information. Anyof the 28 sectors following the root directory may be used as a headingsector.

Sync information is located at the start of each heading sector.

A header follows the sync information in each heading sector. Categoryinformation in the tenth byte of the header is set to "11111111" ("FFh")to indicate that the sector is a heading sector for character ordocument information. Category information in the tenth byte of theheader is set to "11111110" ("FEh") to indicate that the sector is aheading sector for dot data, that is, an image.

Index information in the header indicates how many heading parts,defined below, are contained in the heading sector.

The last four bytes of the header of a heading sector are set to "MINX".As is the case with CAT and directory sectors, the recording/reproducingapparatus 10 refers to the system ID "MINX" to determine if the sectorcontains management information for user data.

A data area of 2048 bytes follows the header in each heading sector.Heading parts are recorded in the data area and contain referenceinformation. Each heading part is referenced from a directory entry byrecording the sector number and part number of the heading part in theheading sector index information (Index 0, Index 1) of the directoryentry, as described above.

Each heading part for character information has a length of 64 bytes(Hd-data 0 to Hd-data 63) and is created by the controller 21 sampling aspecified location within a data file, such as its head or startingcharacters. Alternatively, the heading part may include a characterportion specified by the user or by an application program. A maximum of32 heading parts for character data may be recorded in the data area ofa heading sector.

Each heading part for dot data has a length of 512 bytes (Hd-data 0 toHd-data 511) and is created by the controller 21 sampling a specifiedlocation within the dot data file or by arranging a related graphicpattern (a so-called icon) corresponding to the data file. A maximum of4 heading parts for dot data may be recorded in the data area of aheading sector.

The reference information recorded in each heading part facilitates fileselection by the user, for example, by making it easier to distinguishthe contents of a file, and allows program retrieval, for example, by aparameter other than a file name.

For example, when a data file contains character information, theheading parts can be used for keyword retrieval. When there are manydirectories, it may be impractical to retrieve a file based only on aspecific keyword, keyword based file retrieval is often possible basedon the information in the heading parts referred to by each directoryentry. Since the heading sectors are usually in the same cluster as thedirectory entry, fast keyword retrieval is realized.

As described above, the data U-TOC comprising CAT sectors, directorysectors and heading sectors allows management of user data. This dataU-TOC is useful on a recording medium used by data processing machinesfor inputting/outputting (and recording/reproducing) document and image(dot) data files and their file names. User or non-audio data managementis accomplished substantially independently from audio data management.

FIGS. 19-22 are diagrams showing the structure of data sectors which maybe recorded by a user on the recording medium 1. It will be recalledthat the minimum unit for recording and/or reproducing (i.e., the inputunit for the encoder 30 in FIG. 2 and the output unit for the decoder 28in FIG. 2) is one cluster.

FIG. 19 generally shows the format of a data sector for the userrecordable area. It will be appreciated that the sectors in the dataU-TOC also have this general format. Each sector includes 4×588 bytes.

The first 12 bytes of the sector are synchronization patterns. A syncpattern used with CD-ROM recording media may be employed with arecording medium according to the present invention.

The following 16 bytes are the header for the sector.

A data area of 2048 bytes follows the header.

An additional area of 276 bytes (Aux 0 to Aux 275) follows the dataarea. In modes 1 and 2, the additional area contains error detection andcorrection data.

FIG. 20-22 show data sectors having the three error correction modesmentioned above.

When the ninth byte of the header (Mode) is "00000000" ("00h"),"00000001" ("01h"), or "00000010" ("02h"), the first mode (mode 0),second mode (mode 1), or third mode (mode 2) is indicated, as shown inFIGS. 20, 21, 22, respectively.

In mode 0, an area for error detection and correction data is notparticularly provided. That is, the additional area bytes (Aux 0 to Aux275) are undefined. For a mode 0 sector, only CIRC code error detectionand correction is implemented in the decoder 28 shown in FIG. 2. As iswell known, a CIRC code has a reasonably good error correction ability.

In mode 1, four bytes of error detection and correction parity code data(EDC 0 to EDC 3) are provided for detecting and correcting errors in theadditional area following the data area. A generating polynomial for theparity code bytes may be:

    P(x)=(x.sup.16 +x.sup.15 +x.sup.2 +1)×(x.sup.16 x.sup.2 +x+1)

The remaining bytes (Aux 0 to Aux 271) of the additional area areundefined. For a mode 1 sector, an error can be detected only by digitalsignal outputs from the decoder 28 shown in FIG. 2 without using anerror detection result from the decoder 28 for the reproducedinformation from the disc.

In mode 2, the entire additional area contains error detection andcorrection data. For example, P parity (P-parity 0 to P-parity 171) maybe provided in the first 172 bytes of the additional area and Q parity(Q-parity 0 to Q-parity 103) may be provided in the remaining 104 bytesof the additional area. An error correcting ability of about 80 bytes inmaximum is thus achieved. The P parity and Q parity data are arranged inthe same manner as the Reed Solomon code having a distance (26, 24) withGalois Field (28) adopted for CD-ROM.

FIG. 23 is a flow chart of operation of the recording/reproducingapparatus 10 using the data U-TOC.

When the disc 1 is inserted in the apparatus 10, the P-TOC is read intothe buffer RAM 33 (step F101).

If the P-TOC is not found, error processing is carried out consideringthat it is not an adequate disc (steps F102 and 103), such as displayingan appropriate message to the user.

After the P-TOC data is read in, the audio U-TOC start address UST_(A)is obtained to identify the position of the audio U-TOC, and the systemcontroller 21 of FIG. 2 determines whether the audio U-TOC start addressUST_(A) is smaller than cluster address "20h" (step F104).

If UST_(A) is less than or equal to "20h", a start address Ad (DU) ofthe data U-TOC is set to (USTA+"10h"), because there is room forrecording three consecutive clusters of data U-TOC in the control areafor management data after the audio U-TOC (step F105).

If UST_(A) is greater than "20h", the controller 21 determines whetherUST_(A) is smaller than "30h" (step F106).

If UST_(A) is larger than "30h", the audio U-TOC is not recorded at anappropriate position as the at least one cluster of the audio U-TOCcannot be recorded in three consecutive clusters of the control area formanagement information, so error processing is carried out (step F103).

If UST_(A) is less than or equal to "30h", the start address Ad (DU) ofthe data U-TOC is set to (USTA-"10h"), because there is room forrecording three consecutive clusters of data U-TOC in the control areafor management data before the clusters of the audio U-TOC (step F107).

After the address of the data U-TOC is determined as described above,the recording/reproducing apparatus 10 waits to be instructed to record,reproduce or erase data (step F108).

When the apparatus 10 is instructed to reproduce data, the data U-TOC atthe address Ad (DU) is accessed (step F109).

If no data U-TOC is found, the controller 21 determines that no datafile has been previously recorded and no data U-TOC has been produced,so that processing for the condition of "no file found" is carried out(steps F110 and F112).

If a data U-TOC is found at the address Ad (DU), the data U-TOC is readto obtain retrieval information for the data file to be played backusing the directory and heading data stored therein (step F111).

If retrieval information for the requested data file is found, theaddress of the data file is accessed (steps F113 and F114) and the datafile is read into the buffer RAM 33 (step F115). More specifically, anaddress of the head cluster of the data file to be reproduced isobtained from the directory information and the cluster linkage shown inthe CAT is used to access the clusters containing the data file.

If retrieval information for the requested data file is not found, errorprocessing is carried out (steps F113 and F112), such as providing anappropriate display to the user.

When the apparatus 10 is instructed to erase data, the controller 21accesses the data U-TOC in the address AD (DU) (step F116).

If the data U-TOC is not found, error processing is carried out assumingno data file or data U-TOC has been previously recorded (steps F117 andF123), such as providing an appropriate display to the user.

If the data U-TOC is found at the address Ad (DU), the data U-TOC isread to obtain retrieval information for the data file to be erasedusing the directory and heading data stored therein (step F118).

If retrieval information for the specified data file is found, thedirectory entry in the data U-TOC is deleted (the bytes wherein thedirectory entry is recorded are marked as available for use) and thedata U-TOC is otherwise suitably updated (steps F119 to F122).

If retrieval information for the specified data file is not found, errorprocessing is implemented considering that there is no appropriate file(steps F119 and F123), such as providing an appropriate display to theuser.

When the apparatus 10 is instructed to record data, the controlleraccess the address AD (DU) (step F124).

If no data U-TOC is found (step F125), the disc is considered to be adisc on which neither a data file nor a data U-TOC has been previouslyrecorded, although audio files may have been recorded on the disc. Theaudio U-TOC start address UST_(A) is accessed (step F129), and then itis determined whether an audio U-TOC exists (step F130). If no audioU-TOC exists, the disc is considered to be a virgin disc on whichneither audio nor non-audio data has been recorded, and the processor 21calculates the recordable capacity of the disc, based on the P-TOCinformation, to obtain the capacity of the empty area (step F132). Ifthe audio U-TOC exists, the processor 21 calculates the capacity of theempty area, shown as the regions NA1, D1, NA2, that is, the regionsavailable for recording data and shown in FIG. 5, as indicated by thepointer P-FRA, shown in FIG. 7 (step F131).

After the capacity of the empty area has been determined, the processor21 checks whether this capacity is sufficient for recording the datafile to be recorded (step F134).

If the empty area is determined to be smaller than the volume of thedata file to be recorded, error processing is carried out (step F135),such as providing an appropriate display to the user.

If the empty area has sufficient capacity to accommodate the data fileto be recorded, then the data file is recorded in the empty area (stepF136). The audio U-TOC and data U-TOC are suitably updated.Specifically, the updating includes modifying the list of free areasidentified by the pointer P-FRA in the audio U-TOC. The area allottedfor user data recording, for example, the area D₁ in FIG. 5, is updatedby adjusting appropriate ones of the pointers P-TNO 1 through P-TNO 255in the audio U-TOC. If no data U-TOC exists, a new data U-TOC isproduced at the address Ad (DU) and updated (step F137).

If the data U-TOC is found at the address Ad (DU) (step F125), a size(volume) of the data file to be recorded is compared with the empty areaEA in the data U-TOC to determine whether enough capacity exists in thearea already allocated for user data (step F126).

If the empty area EA has sufficient capacity for the data file to berecorded, the data file is recorded in the empty area EA on the disc(step F127), the data U-TOC is suitably updated or initialized (stepF128) and the processing is finished.

If the empty area EA has insufficient capacity for the data file to berecorded, the audio U-TOC is accessed to expand the area allocated foruser data recording (step F133). Then, the new total empty area iscompared with the size of the data file to be recorded (step F134), andthe file is recorded (steps F136 to F137) or error processing is carriedout (step F135), as described above.

All of the input/output means, that is, the data displaying means, datacommunicating means, image scanner means, key input means and means forconverting from character data to displayable font, shown in FIGS. 1 and2, are not necessarily provided in a recording or reproducing apparatusaccording to the present invention.

It will be appreciated that other data input/output means may be used inan apparatus according to the present invention.

An apparatus or recording medium according to the present invention maybe used for recording and/or reproducing only user data, that is, notaudio data. In this case, the input/output portions used exclusively foraudio signals (the encoder 37, decoder 38, A/D converter 36, D/Aconverter 39, etc.) are unnecessary.

Although an illustrative embodiment of the present invention, andvarious modifications thereof, have been described in detail herein withreference to the accompanying drawings, it is to be understood that theinvention is not limited to this precise embodiment and the describedmodifications, and that various changes and further modifications may beeffected therein by one skilled in the art without departing from thescope or spirit of the invention as defined in the appended claims.

What is claimed is:
 1. A recording apparatus for use with a recordingmedium for recording thereon first management information relating to afirst type of information, second management information relating to asecond type of information, said second type of information beingdifferent than said first type of information and one of said first andsecond types of information being user data, said apparatuscomprising:means for recording on said medium said first managementinformation, said second management information and said first andsecond types of information in first, second and third areas,respectively, said means for recording being operative to record saiduser data and the management information for said user data inrespective sectors on said recording medium, each of said sectorsincluding category information; and control means for generating saidfirst management information when said first type of information isrecorded by said means for recording and for generating said secondmanagement information when said second type of information is recordedby said means for recording, said control means being operative to eraseeach of said sectors by setting its category information to apredetermined value.
 2. The apparatus as in claim 1, wherein the userdata is recorded in files having at least one sector, and said controlmeans is operative to erase one of said files by setting the categoryinformation for the sectors in which said one file is recorded and thesectors in which the management information for said one file isrecorded to said predetermined value.
 3. The apparatus as in claim 1,wherein the management information for said user data includesallocation information identifying the usage of recordable portions ofsaid recording medium, and said control means is also operative toupdate said allocation information when erasing at least one of saiduser data and the management information for said user data.
 4. A methodof recording on a recording medium first management information relatingto a first type of information, second management information relatingto a second type of information, said second type of information beingdifferent than said first type of information and one of said first andsecond types of information being user data, said method comprising thesteps of:recording on said medium said first management information,said second management information and said first and second types ofinformation in first, second and third areas, respectively, said step ofrecording including recording said user data and the managementinformation for said user data in respective sectors on said recordingmedium, each of said sectors including category information and beingerasable by setting its category information to a predetermined value;and generating said first management information when said first type ofinformation is recorded and generating said second managementinformation when said second type of information is recorded.
 5. Themethod as in claim 4, wherein said user data is recorded in files havingat least one sector and further comprising the step of erasing one ormore of said files by setting the category information for the sectorsin which said one or more files are recorded and for the sectors inwhich the management information for said one or more files is recordedto said predetermined value.
 6. The method as in claim 5, wherein themanagement information for said user data includes allocationinformation identifying the usage of recordable portions of saidrecording medium, and said erasing includes updating said allocationinformation when erasing at least one of said user data and themanagement information for said user data.
 7. A recording apparatus foruse with a recording medium for recording thereon first managementinformation relating to a first type of information, second managementinformation relating to a second type of information, said second typeof information being different than said first type of information, saidapparatus comprising:means for recording on said medium said firstmanagement information, said second management information and saidfirst and second types of information in first, second and third areas,respectively, and control means for generating said first managementinformation when said first type of information is recorded by saidmeans for recording and for generating said second managementinformation when said second type of information is recorded by saidmeans for recording.
 8. The apparatus as in claim 7, wherein one of thefirst and second management information includes allocation informationidentifying usage of recordable portions of said recording medium, andsaid control means is operative to update said allocation informationwhen recording at least one of said first and second types ofinformation.
 9. The apparatus as in claim 8, wherein said control meansis operative to update said allocation information when recording eachof said first and second types of information.
 10. The apparatus as inclaim 7, wherein said control means is operative to generate a firstidentification code as part of said first management informationindicating said first type of information and to generate a secondidentification code as part of said second management informationindicating said second type of information.
 11. The apparatus as inclaim 10, wherein one of said first and second identification codes is"MINX".
 12. The apparatus as in claim 11, wherein the other of saidfirst and second identification codes is "MINI".
 13. The apparatus as inclaim 7, wherein said first management information includes boundaryinformation identifying at least one portion of said third areaallocated for recording said second type of information, wherein saidapparatus also includes means for receiving a file containing saidsecond type of information, and wherein said control means is operativeto determine whether said at least one portion of said third area hasadequate capacity for recording said file.
 14. The apparatus as in claim13, wherein said control means is also operative to adjust said boundaryinformation in said first management area so that said at least oneportion, as adjusted, has adequate capacity for recording said file whensaid control means determines said at least one portion of said thirdarea lacks adequate capacity for recording said file.
 15. The apparatusas in claim 14, wherein said first management information includes alist of free areas on said recording medium, and said control means isalso operative to adjust said list of free areas when adjusting saidboundary information.
 16. The apparatus as in claim 7, wherein one ofsaid first and second types of information is user data.
 17. Theapparatus as in claim 16, wherein the other of said first and secondtypes of information is audio data.
 18. The apparatus as in claim 16,wherein the management information for user data includes referenceinformation, and the control means is also operative to sample the userdata to obtain the reference information.
 19. The apparatus as in claim16, wherein said means for recording is operative to record the userdata and the management information for user data in respective sectorson said recording medium, each of said sectors including categoryinformation, and said control means is operative to erase said each ofsaid sectors by setting its category information to a predeterminedvalue.
 20. The apparatus as in claim 19, wherein the user data isrecorded in files having at least one sector, and said control means isoperative to erase one of said files by setting the category informationfor the sectors in which the file is recorded and the sectors in whichthe management information for the file are recorded to saidpredetermined value.
 21. The apparatus as in claim 19, wherein themanagement information for user data includes allocation informationidentifying the usage of recordable portions of said recording medium,and said control means is also operative to update said allocationinformation when erasing at least one of the user data and themanagement information for user data.
 22. A method of recording for usewith a recording medium for recording thereon first managementinformation relating to a first type of information, second managementinformation relating to a second type of information, said second typeof information being different than said first type of information, saidmethod comprising the steps of:recording on said medium said firstmanagement information, said second management information and saidfirst and second types of information in first, second and third areas,respectively, and generating said first management information when saidfirst type of information is recorded by said means for recording andgenerating said second management information when said second type ofinformation is recorded by said means for recording.
 23. The method asin claim 22, wherein one of the first and second management informationincludes allocation information identifying usage of recordable portionsof said recording medium, and further comprising the step of updatingsaid allocation information when recording at least one of said firstand second types of information.
 24. The method as in claim 23, whereinsaid step of updating updates said allocation information when recordingeach of said first and second types of information.
 25. The method as inclaim 22, wherein the step of generating said first managementinformation includes generating a first identification code indicatingsaid first type of information; and the step of generating said secondmanagement information includes generating a second identification codeindicating said second type of information.
 26. The method as in claim25, wherein one of said first and second identification codes is "MINX".27. The method as in claim 26, wherein the other of said first andsecond identification codes is "MINI".
 28. The method as in claim 22,wherein said first management information includes boundary informationidentifying at least one portion of said third area allocated forrecording said second type of information, and further comprising thesteps of receiving a file containing said second type of information,and determining whether said at least one portion of said third area hasadequate capacity for recording said file.
 29. The method as in claim28, further comprising the step of adjusting said boundary informationin said first management area so that said at least one portion, asadjusted, has adequate capacity for recording said file when said stepof determining determines that said at least one portion of said thirdarea lacks adequate capacity for recording said file.
 30. The method asin claim 29, wherein said first management information includes a listof free areas on said recording medium, and further comprising the stepof adjusting said list of free areas when adjusting said boundaryinformation.
 31. The method as in claim 22, wherein one of said firstand second types of information is user data.
 32. The method as in claim31, wherein the other of said first and second types of information isaudio data.
 33. The method as in claim 31, wherein the managementinformation for user data includes reference information, and furthercomprising the step of sampling the user data to obtain the referenceinformation.
 34. The method as in claim 31, wherein said step ofrecording records the user data and the management information for userdata in respective sectors on said recording medium, each of saidsectors including category information, and further comprising the stepof erasing said each of said sectors by setting its category informationto a predetermined value.
 35. The method as in claim 34, wherein theuser data is recorded in files having at least one sector, and the stepof erasing one of said files includes setting the category informationfor the sectors in which the file is recorded and the sectors in whichthe management information for the file are recorded to saidpredetermined value.
 36. The method as in claim 34, wherein themanagement information for user data includes allocation informationidentifying the usage of recordable portions of said recording medium,and said step of erasing includes updating said allocation informationwhen erasing at least one of the user data and the managementinformation for user data.